title: Monitoring and characterization of oseltamivir-resistant pandemic (H1N1) 2009 virus, Japan, 2009-2010.
abstract: To monitor and characterize oseltamivir-resistant (OR) pandemic (H1N1) 2009 virus with the H275Y mutation, we analyzed 4,307 clinical specimens from Japan by neuraminidase (NA) sequencing or inhibition assay; 61 OR pandemic (H1N1) 2009 viruses were detected. NA inhibition assay and M2 sequencing indicated that OR pandemic (H1N1) 2009 virus was resistant to M2 inhibitors, but sensitive to zanamivir. Full-genome sequencing showed OR and oseltamivir-sensitive (OS) viruses had high sequence similarity, indicating that domestic OR virus was derived from OS pandemic (H1N1) 2009 virus. Hemagglutination inhibition test demonstrated that OR and OS pandemic (H1N1) 2009 viruses were antigenically similar to the A/California/7/2009 vaccine strain. Of 61 case-patients with OR viruses, 45 received oseltamivir as treatment, and 10 received it as prophylaxis, which suggests that most cases emerged sporadically from OS pandemic (H1N1) 2009, due to selective pressure. No evidence of sustained spread of OR pandemic (H1N1) 2009 was found in Japan; however, 2 suspected incidents of human-to-human transmission were reported.
authors.affiliation: National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ujike
authors.forename: Miho
authors.initials: M
authors.lastname: Ejima
authors.forename: Akane
authors.initials: A
authors.lastname: Anraku
authors.forename: Kozue
authors.initials: K
authors.lastname: Shimabukuro
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Obuchi
authors.forename: Noriko
authors.initials: N
authors.lastname: Kishida
authors.forename: Xu
authors.initials: X
authors.lastname: Hong
authors.forename: Emi
authors.initials: E
authors.lastname: Takashita
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Fujisaki
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Yamashita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Horikawa
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Akio
authors.initials: A
authors.lastname: Oguchi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fujita
authors.forename: Masato
authors.initials: M
authors.lastname: Tashiro
authors.forename: Takato
authors.initials: T
authors.lastname: Odagiri
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D007251:Influenza, Human / Q000188:drug therapy / Q000453:epidemiology / Q000635:transmission / Q000821:virology*; D007564:Japan / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D009439:Neuraminidase / Q000235:genetics; D053139:Oseltamivir / Q000494:pharmacology* / Q000627:therapeutic use; D058873:Pandemics; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D053139:Oseltamivir; D009439:Neuraminidase